OFDM Time of Arrival Determination via Phase Rotation
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Solution Overview
Problem
In wireless communication systems, determining the time of arrival of signals between nodes, such as base stations and user equipment, is challenging due to the complexity of existing methods, which often require continuous transmission of positioning signals and lack efficient ways to identify the shortest path for accurate location determination.
Innovation Solution
The method involves determining if a received signal traveled via a shortest path in an OFDM system by identifying flat fading in the frequency domain, calculating the phase rotation, and using this information to estimate the time of arrival, thereby simplifying the baseband modem structure for positioning measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If continuous transmission of positioning signals is used, then positioning accuracy is improved, but device complexity and resource consumption increase
Solution Approach 1:
The patent extracts only the necessary positioning information from continuous signals by identifying the shortest path through flat fading detection in the frequency domain. This allows the system to obtain accurate time of arrival measurements without requiring continuous transmission of dedicated positioning signals, thereby reducing device complexity while maintaining positioning accuracy.
Solution Approach 2:
The system performs preliminary identification of the shortest path using flat fading characteristics before conducting time of arrival measurements. By pre-identifying which signal path to use for positioning, the system avoids the need for continuous positioning signal transmission and complex real-time signal processing, thus reducing resource consumption while preserving measurement precision.
2Loss of information
If existing time of arrival determination methods are used, then positioning information is obtained, but resource consumption and complexity increase
Solution Approach 1:
The patent enables the system to determine time of arrival using existing communication signals that are already being transmitted for data communication. By utilizing the flat fading characteristics of these existing signals, the system obtains positioning information without requiring additional dedicated positioning signals, thereby reducing resource consumption while maintaining positioning information accuracy.
Solution Approach 2:
The system uses communication signals that serve dual purposes: both data transmission and positioning measurement. By detecting flat fading in the frequency domain of these universal signals, the system extracts time of arrival information without requiring separate positioning signal transmissions, thus reducing resource consumption while preserving positioning information accuracy.
3Measurement precision
If shortest path identification is implemented, then positioning accuracy is enhanced, but measurement complexity increases
Solution Approach 1:
The patent replaces complex mechanical or algorithmic shortest path detection methods with a simpler frequency domain analysis approach. By detecting flat fading characteristics in the frequency domain, the system can identify the shortest path using straightforward signal processing techniques rather than complex path-finding algorithms, thus enhancing time of arrival accuracy while reducing measurement complexity.
Data Source
AI summary
A method can include determining that a received signal traveled via a shortest path from a transmitting device to a receiving device of an orthogonal frequency-divisional multiplexing (OFDM) communication system, determining a phase rotation of the received signal, and determining a time of arrival based on the determined phase rotation.